Our ability to understand cellular function in normal health and disease from the macro to micro to nano scale depends on the capabilities of state-of-the-art advanced instrumentation. The NIH funded projects described in this S10 application require enhanced imaging resolution, deeper tissue imaging and the ability to image in live animals for their fluorescence microscopy applications to advance to the next level. A Leica TCS Sp8 MP multiphoton microscope is requested and will be located in the UMKC Confocal Microscopy Core. It will be operated as a shared resource to support the research programs of a core group of NIH funded major and minor users in the UMKC Schools of Dentistry, Medicine, Nursing and Pharmacy as well as in the University of Kansas Medical Center and the Kansas City University of Medicine and Biosciences. The user group has a diverse research emphasis on musculoskeletal research, neural/vision research, developmental biology, dental research, nephrology and drug delivery research. To accommodate the range of project applications, the instrument will be configured for multiphoton imaging on live animals, live cells and tissue explants as well as fixed cell and tissue specimens and for optical sectioning/3D imaging. One of the projects that will employ this technology is investigating the mechanisms of assembly of bone extracellular matrix (ECM), using time lapse imaging with novel transgenic mice expressing a GFP-tagged collagen fusion protein. These studies are providing novel insights into the dynamic nature of bone matrix assembly and the role of cell motility in the assembly process. The role of the osteocyte in regulating skeletal responses to mechanical loading and in regulating muscle function is the focus of three of the participating projects. One project examines the dynamic properties of osteoblasts and osteocytes using lineage reporters combined with time lapse imaging to gain insight into the process by which osteoblasts differentiate into osteocytes. Other projects are focused on the role of mitochondria in degenerative muscle diseases, the role of hyperfiltration in glomerular injury, muscle contractile function and calcium signaling, developmental heart morphogenesis and morphogenetic tissue movements in early embryos. Acquisition of the Leica TCS Sp8 MP multiphoton technology will allow us to take these projects to the next level by providing our investigators with the ability t perform deep tissue fluorescence imaging in live animals and cell and explant culture systems as well as in fixed tissue samples. There is currently no capability for this type of imaging at UMKC or the other participating institutions and therefore this instrument will be a local resource to provide access to investigators who need multiphoton capabilities. Acquisition of this technology will advance discoveries regarding musculoskeletal health, development, aging, vision, dental restorations and drug delivery.